Expansible piston



June 23, 1925.

O. WIGGERS ET AL EXPANSIBLE PISTON Filed Jan. 22. 1923 2 Sheets-Sheet 1was m5 W? 1% m B 1 June 23, 1925.

O. WIGGERS ET AL EXPANS IBLE P'iSTON Filed Jan. 22. 1923 2 Sheets-Sheet2 IN VEN TOR.

Q ff m 6w 0 Z ,M

Patented June 23, 1925. D

'\ UNITED STATES PATENT'OFFICE.

OTTO WIGGERS AND JOHN WIGGEBS, 0F WALLA WALLA, :WA'SHINGTON.

EXPANSIBLE PISTON.

Application filed January 22, 1923. Serial No. 614,259.

To all whom it may concern: Be it known. that we, O'r'ro WIGGERS andJOHN WIGGERS, citizens of the N etherlands,

residing at Walla Walla, in the county of Walla Walla and State ofWashington, have invented certain new and useful Improvements inExpansible Pistons, of which the following is a specification.

This invention relates to 'expansible pistons, such as used in internalcombustion engines, and has as one of its objects to provide a pistonthat may be expanded to. fit

the cylinder of the engine when wear has occurred and to maintainconstant the increased size until further wear occurs.

A further object of the invention is to provide" an expansible pistonthat is practically as cheap to manufacture as those in use at thepresenttime and which, by reason of its expansion will provide greaterservice.

WVith this and other objects in view reference is had to the accopanying drawings in which of a piston Fig.' 7 shows a sectional view ofpart of a piston with one form of in place;

Fig. 8 is a similar viewof Fig. 7 showing a modification of theexpanding means;

'Fig. 9 is a plan view of ,a special head for a fastening bolt, taken'onthe line 99 of Fig. 7. J

Fig. 10 is a side elevation of the fastening bolt shown in lan in' Fig.9;

. Fig. 11 is a slde elevation of a tapered bolt expanding means as shownin Fig. 8;

Fig. 12 shows an enlarged perspective view of a wedge substitute for atapered bolt; and I Fig. 13 shows another modified form of expandingmeans, in an inverted position.

Having reference to the-drawings like nu merals refer to like partsthroughout the several views and the numeral 1 refers to a pistonprovided with the usual. skirting 2 carrying the wrist pin bosses 3, andguide portions 4. l

In the skirting 2 is provided'a series of slots, which, as they areunited, will be termed a slot, that together form an anchor shaped slot5 consisting of a diagonal slot 6, tal slot 8.

.The out for the diagonal slot is made by starting the out at the pointshown as 9 a vertical slot 7, and a horizonmidway between the bosses 3and at a point I nearly opposite the upper part 10 of the bosses 3, andcutting-downward and inward to a point 11 near and approximately on ,alevel with the lower part 12 of said bosses; the vertical slot 7 is outlongitudinally of the piston starting at the lower edge 13 of theskirting and cutting up to intersect the diagonal slot 6 at the point14; and the horizontal slot 8 is out slightly above and parallel to thelower edge 13 and is bisected by the vertioalaslot 7.

It is well known inthe art that pistons should be made as light aspossible therefore they are hollowed out, as at 15, leaving a sufiicientbearing surface 16, however, the wearing side, i. e., on the sideopposite to thewrist pin, to properly guide the piston in the cylinder,not shown.

The skirtin then at this bearing part 16 is obviously 0% fact that it"isthe bearing art that must contact the cylinder wall, ma es it essentialthat the slots should be made herein to provide the proper expansion ofthe piston.

Within the piston is mounted the expanding means of which there areseveral modifications shown in the drawings, all consistthicker metal,which with the ing however, of the one principle of forcing an expansionby means of a wedge.

One means for expandingthe iston consists of projections 17 having wedgeshaped recesses 18, similar to that shown in Fig. 6, positioned one oneach side of the slot 5 and made integralwith the skirting 2, therecesses being designed to receive a wedge 19 which when forced thereinby any suitable means will expand the skirting 2, slots 20 being cut ina reinforcing rib 21 to provide for equal expansion of the skirting.

Another means of expanding the skirting consists of mounting anexpansible ring 22 Within the skirting, the ring being prov ded withabutting ends 23, both of which are recessed wedge shape to accommodatethe wedge 19 which in turn is forced therein by a suitable means. Inusing the ring 22 it is desirable to have some means of preventing unduemovement in a direction longitudinal of the piston and for this purposeribs 24; are provided, the ribs being out integral with the piston.

The wedges 19 used for the purpose of expansion may be conical in shape,as shown in Figs. 7 8,

11 and 13, or may be rectangular as shown in Fig. 12, and the wedges maybe moved, i. e. forced into the wedge shaped recesses 18, by means of abolt 25 having an irregular shaped head 26 to engage the side wall 27 ofthe skirting 2 to prevent turning, with the conical shaped wedge 19having a nut 28 to threadedly engage the bolt 25 (see Fig. 7) wherewithto draw the wedge the proper distance in the recesses, or with a bolt 25provided with a conical shaped head, which in turn is provided with aslot 29 to accommodate a driver, as shown in Fig. 8. In both of thesecases a projecting lug, 30 may be used to draw against, and cotter pins31 may be used to prevent accidental loosening of the arts, and in thecase of the means, shown in Fig. 7, the bolt 25 is assembled in the lugby means of a slot 32 cut therein, as shown in Fig. 9.

In Fi 13 is shown another modification and in t is case the head 33 ofthe boltbears against the ring 22, and the wedge 19, which is slidableon the bolt, is seated by the castellated nut 34, held in place asbefore by the cotter pin 31.

Where the rectangular wedge is used, the

recesses are correspondingly designed to register therewith and may beused where a more perfect fit of. the parts is required.

In use, the piston first being slotted, the wedges are inserted to placeand by screwing are brought up to the proper place, this beingdetermined by micrometers or other means.

Obviously in the means designed as shown in Fig. 8,'the piston wouldhave to be removed to make the expansion as the cotter pin 31 must firstbe recessed which can only be done by removing the piston, sufiicient atleast, to uncover the cotter pin when it may be removed. In the otherdesigns, however, adjustments may be made while the piston is in place.

' Having thus described our invention, we claim- 1. In an expansiblepiston, a slotted skirt-.

ing, a slotted reinforcing rib within said skirting, the slots thereofproviding for equal expansion, wedgeshaped projections one on each sideof'the slot in the interior of said skirting, and means to expand saidprojections and with them said skirting.

2. In an expansible piston, a slotted skirting, projections on theinterior of said skirt- 7 ing, positioned one on each side of the slotand provided with wedge shaped recesses, lugs extending inwardl fromsaid skirting, and a tapered bolt in t readed engagement with said lugsand in sliding engagement with the wedgeshaped recesses of the projec'tions to expands said piston.

In testimony whereof O'rro WIGGERS and JOHN IVIGGERS affix theirsignatures.

OTTO WIGGERS. JOHN WIGGERS.

